FileDate() throws unexpected error

These evaluator commands work fine but still throw an error.

@nodeselect
@output:{=filepath=}
@output:{=FileDate(filepath)=}
XML
<?xml version="1.0"?>
<button backcol="none" display="both" label_pos="right" textcol="none">
	<label>Test FileDate</label>
	<icon1>#newcommand</icon1>
	<function type="normal">
		<instruction>@nodeselect</instruction>
		<instruction>@output:{=filepath=}</instruction>
		<instruction>@output:{=FileDate(filepath)=}</instruction>
	</function>
</button>

Fixed in the next beta. Thanks for the report!